Embodiments of the invention relate to a rollover-sensing system, and particularly to a rollover-sensing system that discriminates and senses soil-tripped rollover events, curb-tripped rollover events, or both.
Vehicle rollover events are situations in which vehicle occupants are at risk of serious injury. To protect the vehicle occupants from injury, vehicles typically include restraint devices such as airbags and seatbelts that can be actuated during a rollover or possible rollover. The accuracy and timeliness of deployment and actuation of these restraint devices are factors in their effectiveness.
There are different types of rollover events. For example, a vehicle can be involved in an upward rollover event when the vehicle is traveling in a forward direction, and then travels across an object or an inclined surface resulting in an upward roll. A vehicle can be involved in a downward rollover event when the vehicle is traveling in a forward direction, and then travels across an object or a declined surface resulting in a downward roll. A vehicle can be involved in an un-tripped rollover event when the vehicle is traveling and tilting beyond its critical stability angle.
A vehicle can be involved in a tripped rollover event when the vehicle is sliding laterally and hits an obstacle. For example, a vehicle can be involved in a soil- or curb-tripped rollover event. A soil-tripped rollover event occurs when the vehicle is initially traveling on a roadway, and begins a slide that takes the vehicle off the roadway. As the vehicle slides off the roadway, the wheels of the vehicle may contact unpaved ground, grass, or soil. Soil may build up near the wheels of the vehicle and create a lip or mound of soil. The mound may reach a sufficient size or configuration such that it acts as a barrier over which the wheels and, consequently, the vehicle trip. A curb-tripped rollover event occurs when the vehicle is initially traveling on a roadway, and then slides sideways into a curb that acts as a barrier over which the wheels and, consequently, the vehicle trip. In such a case, a lateral impact force is typically exerted against an obstacle, and is stronger than that of a soil-tripped event.